A federal judge in Washington, D.C., handed House Democrats their first legal victory Monday in their fight to obtain President Trump's financial records, in this case from Trump's accounting firm Mazars USA. "It is simply not fathomable," Judge Amit Mehta wrote, "that a Constitution that grants Congress the power to remove a president for reasons including criminal behavior would deny Congress the power to investigate him for unlawful conduct — past or present — even without formally opening an impeachment inquiry." Mehta gave Trump a week to appeal, and Trump said he will do so.

The next legal battle involves a subpoena from the House Financial Services Committee for Trump's business and personal financial records from Deutsche Bank and Capital One. U.S. District Judge Edgardo Ramos in Manhattan is hearing Trump's motion to block that subpoena on Wednesday, and House lawyers quickly reminded Ramos that Mehta had just rejected "a substantially similar challenge by President Trump."

NEW: That was fast.

Counsel for the House Committees informed the SDNY judge that Trump just lost his similar challenge in the District of D.C.

Ramos will be hearing Trump's request for a preliminary injunction, a step Mehta skipped, but Trump's basic legal argument is broadly similar in both cases: Congress is inappropriately investigating Trump's personal finances, without any legitimate legislative reason. If Ramos allows the subpoena, Trump's lawyers wrote last week, "nonstop investigations into the personal lives of presidents" will become "the new normal."

Last week, U.S. District Judge Amit Mehta in Washington, D.C., ruled that he would fast-track President Trump's lawsuit to block his accounting firm from handing eight years of his financial records to the House Oversight Committee, which subpoenaed them. Mehta said he would decide the merits of the case after a hearing on Tuesday, skipping a preliminary phase. On Monday, Trump's lawyers said Mehta is moving too fast.

"The sole question before the court — Is the House Oversight Committee's issuance of a subpoena to Mazars USA LLP for financial records of President Donald Trump and various associated entities a valid exercise of legislative power? — is fully briefed, and the court can discern no benefit from an additional round of legal arguments," Mehta, an Obama appointee, wrote Thursday.

Trump's lawyers disagreed on Monday, saying they need more time to gather evidence and develop their legal arguments in the lawsuit they filed. On Monday night, Mehta rejected their request to delay the hearing or narrow its scope but said he will hear their objections on Tuesday.

"The executive branch strategy mostly seems to be a blanket rejection of all attempts at oversight, regardless of the issue, up until the election," Lisa Kern Griffin, a professor of constitutional law at Duke University, tells Reuters. "So any time the calendar is accelerated that probably favors Congress." If the losing side appeals, Mehta's accelerated schedule means an appellate court could get the case by summer, The Washington Post reports.

Last week, retired Supreme Court Justice John Paul Stevens told The Wall Street Journal "the president is exercising powers that do not really belong to him," adding, "I mean, he has to comply with subpoenas and things like that." If the Supreme Court weighs in on the battles between Trump and House Democrats, "I wouldn't want to predict that anybody's going to take the incorrect view," Stevens said. "But certainly, the correct view is pretty clear." Peter Weber

One way or another, Congress will almost certainly obtain President Trump's financial records, "and Republican efforts to investigate the Christopher Steele dossier could be one reason why," writes CNN's Katelyn Polantz. Specifically, Democrats could find an unwitting helper in Rep. Devin Nunes (R-Calif.), a Trump ally who successfully subpoenaed the bank records of Fusion GPS when he was chairman of the House Intelligence Committee.

The House Oversight, Intelligence, and Financial Services committees have subpoenaed Trump's business and personal financial records from his accounting firm, Mazars USA, and lenders Deutsche Bank and Capital One. Like Fusion GPS, Trump has sued his banks and accountants to prevent them from releasing his records. Fusion GPS had to disclose who financed the Steele dossier after losing its fight in federal court, using some of the same arguments Trump's lawyers are testing. U.S. District Judge Amit Mehta has fast-tracked the accounting firm lawsuit, scheduling the first hearing for Tuesday.

"The difficulty that Trump faces is the same one that we faced," Bill Taylor, Fusion GPS's lawyer in the case, tells CNN. "There's a heavy presumption in favor of the validity of a congressional subpoena."

The House Ways and Means Committee has also legally requested Trump's tax returns from the IRS, though Treasury Secretary Steven Mnuchin is fighting that, too. The New York Senate, now controlled by Democrats, approved legislation last week that specifically permits three congressional committees to view the state tax returns of anyone who files in New York, as Trump and many of his businesses did. The State Assembly has enough support to pass the bill, too, though no vote is yet scheduled.

But the important fight might end up being in Mehta's courtroom. "Arguably you could get a lot more information from the accounting firm than you could from the tax returns," former federal tax prosecutor Kevin Sweeney tells CNN. "They'd keep the documentation they used to prepare that return." Peter Weber

The Trump administration is pushing back against House Ways and Means Committee Chair Richard Neal's (D-Mass.) request for President Trump's tax returns, arguing it serves no legitimate policy purpose. The 1924 law Neal is using doesn't require a policy rationale, though Neal has provided one: monitoring how the IRS audits presidents' tax returns. (The last time Congress checked on a sitting president's taxes, Richard Nixon turned to owe the IRS about $477,000.)

Most tax-law experts agree Neal is on firm legal ground in demanding Trump's tax returns to view in private ("executive") session. Before 1924, "the president had the sole and unconditional right to obtain and disclose anyone's tax return information," University of Virginia law professor George Yin tells Vox.But after the Teapot Dome scandal, Congress decided "it had to have the same access to tax information as the president," to investigate the president and the executive branch.

In fact, "the only thorny legal question arises if the full Ways and Means Committee, after debate and a vote in executive session, were to authorize the dissemination of Trump's tax return into the public record of the House," University of Southern California law professor Edward Kleinbard writes in the Los Angeles Times. Unlike the president, who still has the right to view any taxpayer's returns, "tax law expressly permits" the Ways and Means Committee to publicly release such returns, with proper justification. "Does the Ways and Means Committee have a solid reason to put Trump's tax returns in the public House record?" Kleinbard asks. If we get to that point, "it turns out that the Republicans have poisoned their own well."

The only precedent on such a move stems from 2014. Back then, congressional Republicans were on the warpath, insisting that the IRS improperly discriminated against conservative organizations seeking tax-exempt status. ... The committee, voting on party lines, released into the public record tax return information of more than 50 organizations, for absolutely no reason beyond their hope to embarrass Democrats. [Edward Kleinbard, Los Angeles Times]

So "if Trump challenges a public release of his tax information in court," Kleinbard says, "he should fear that Republicans' 2014 political power move could color the outcome." Peter Weber

House Ways and Means Committee Chair Richard Neal (D-Mass.) has asked for six years of President Trump's personal and business tax returns by April 23, using a law that doesn't give Treasury Secretary Steven Mnuchin much wiggle room. On Fox News Sunday, host Chris Wallace asked White House Press Secretary Sarah Huckabee Sanders if Trump will "tell the IRS not to release them?" "We'll have to see what happened on that front," Sanders said.

Sanders repeated the argument from Trump's lawyers and Mnuchin that Neal's stated policy purpose for seeking Trump's tax returns is insufficient or purely partisan, claiming "the only reason that the oversight committee has the ability to request someone's taxes are for the purpose of determining policy." (Whether Neal needs a policy purpose is a question that hasn't been answered by the courts, though the 1924 tax law in question was enacted in response to the Harding administration's Teapot Dome scandal and most legal experts agree Neal's purpose would pass the legal threshold in any case.)

And Sanders raised a new line of attack, not based on the law at all: "Frankly, Chris, I don't think Congress — particularly not this group of congressmen and women — are smart enough to look through the thousands of pages that I would assume that President Trump's taxes will be."

Wallace also asked Sanders how the White House is preparing for information in Special Counsel Robert Mueller's report that "clearly is going to be damaging to the president" — "I don't think it is going to be damaging to the president," she said — and Sanders claimed Trump's repeated praise of WikiLeaks was clearly Trump "making a joke during the 2016 campaign," to which a skeptical Wallace replied: "It was a joke he made over and over again." Watch the entire interview below. Peter Weber

The Democrats in line to lead the Senate and House finance committees say that if their party takes control of either house of Congress in the midterms, they will use their authority to obtain a copy of President Trump's tax returns. "We will do that," Rep. Richard Neal (D-Mass.), in line to chair the House Ways and Means Committee, told The Wall Street Journal. Sen. Ron Wyden (D-Ore.), a longer shot to become chairman of the Senate Finance Committee, said he would request Trump's tax returns, too.

"Under the tax code, the Ways and Means chairman can demand and receive any taxpayer's records from the IRS for confidential review," explains the Journal's Richard Rubin. "Neal wouldn't need approval from the full House, the Senate, or the administration." Neal said if he gets Trump's returns, he'll consult with his staff, House lawyers, and Democratic leaders; they could decide to release some or parts of the returns, which would require a committee vote, keep them confidential, or have them analyzed by nonpartisan analysts. "This has never happened before, so you want to be very meticulous," Neal told the Journal.

Democrats have said they want to see Trump's tax returns — which he promised to release during the campaign but didn't — because they would provide insight into whether he has compromising business ties to Russia or other foreign governments, how he benefits from his tax overhaul, and whether he has avoided paying taxes, a topic of special concern after a New York Times investigation found several instances of dubious tax schemes in his family. Current Ways and Means Committee Chairman Kevin Brady (R-Texas) isn't a fan of the idea, saying his committee's authority "is a powerful oversight tool to be used not for political fishing expeditions," adding: "Most people don't care about the president's tax returns. They care about their own." Before Trump, every president since Richard Nixon released his tax returns. Peter Weber

The tax plan President Trump unveiled on Wednesday is really only a single page of bullet points, but it's already pretty clear that a big beneficiary of the proposals would be super-wealthy chieftains of private real estate empires who have children. One big winner from the proposals would be "pass-through" businesses like the Trump Organization and its hundreds of subsidiaries, where owners file business income on their individual returns — depending on how the law is written, such business owners could pay a 15 percent tax rate instead of an individual rate of up to 35 percent. "Trump is the king of pass-throughs," said Steven Rosenthal at the nonpartisan Tax Policy Center. "He has pass-through businesses everywhere."

Trump's proposal would also eliminate the estate tax and the alternative minimum tax, and the push to reduce or eliminate taxes on profits that U.S. businesses earn overseas would be a boon for the golf courses and hotels the Trump Organization owns or licenses around the world. "Commercial real estate businesses like those controlled by the Trump Organization stand to benefit greatly," too, The Wall Street Journal says, with one provision slashing "tax rates for many property businesses by more than half."

In fact, "it is striking how many of the categories listed above affect the president and his family," says Neil Irwin at The New York Times. "He is a high-income earner. He receives income from 564 business entities, according to his financial disclosure form, and could take advantage of the low rate on 'pass-through' companies. According to his leaked 2005 tax return, he paid an extra $31 million because of the alternative minimum tax that he seeks to eliminate. And his heirs could eventually enjoy his enormous assets tax-free."

Of course the precise amount Trump and his businesses (now held in trust) would save "couldn't be determined because he has declined to release his tax returns," The Wall Street Journal notes. "Still, from what is known about how his businesses are structured, experts estimate the savings would be in the tens of millions of dollars" a year. On Wednesday, Treasury Secretary Steven Mnuchin said flatly that Trump has "no intention" of releasing his tax returns, arguing that "the American population has plenty of information." Peter Weber

On Tuesday night, the White House said that President Trump paid $36.5 million in federal income tax in 2005 on $153 million in reported income, confirming investigative reporter David Cay Johnston's announcement that somebody had anonymously sent him the first two pages of Trump's 1040 form from that year. The forms don't show much — Trump wrote off more than $100 million for what the White House described as a "large-scale depreciation for construction," and he would have paid just $5 million in ordinary income tax if there were no alternative minimum tax — which Trump, incidentally, seeks to abolish.

The fact that the White House confirmed the authenticity of the forms, however, did not stop Trump from tweeting early Wednesday that the whole story is "FAKE NEWS!" from a reporter "who nobody ever heard of."

Does anybody really believe that a reporter, who nobody ever heard of, "went to his mailbox" and found my tax returns? @NBCNews FAKE NEWS!

Johnston — who won a Pulitzer Prize in 2001 for his reporting on loopholes in the U.S. tax code, first met Trump in 1988, and wrote a book about him last year, The Making of Donald Trump — told MSNBC's Rachel Maddow and CNN's Don Lemon on Tuesday night that he suspects Trump himself may have sent him the tax documents.